scholarly journals Design of Rigid Pavement by Self Cured Concrete Utilizing Coarse Fly Ash Aggregates and Curing Admixture

2021 ◽  
Vol 889 (1) ◽  
pp. 012011
Author(s):  
Ajay Rana ◽  
Abhishek Sharma ◽  
Kshitij Jassal

Abstract In concrete industry, a huge amount of natural aggregates is used in the making of concrete every day. The environment is being exploited by mining for the gain of natural aggregates, resulting in an environmental instability in nature. As a result, an alternate source to substitute natural aggregates in concrete is required. A lot of waste materials have gain attention now a days into the concrete industry as a substitute to natural materials. Fly ash, a waste product of thermal power plants, meets the criterion for being utilised as an aggregate substitute in concrete because of its pozzolanic activity. Coarse fly ash is manufactured using a good manufacturing method and is light in weight. Keeping this into view, the impact of partial replacement of natural coarse aggregates with coarse fly ash aggregates produced using the colds bonded method is explored in this paper. The major focus of this study is on testing for flexural strength of self-cured concrete, as flexural strength is a key criterion for rigid pavement design. In this study, coarse fly ash aggregates are utilised in concrete in different proportions to substitute natural aggregates, and the optimal value for flexural strength is determined using a curing additive. The findings of this experiment indicated that when fly ash aggregates and curing additives were used optimally, the flexure strength improved, which is enough for the construction of rigid pavement as criteria fixed by Indian Standards.

Author(s):  
Harshkumar Patel ◽  
Yogesh Patel

Now-a-days energy planners are aiming to increase the use of renewable energy sources and nuclear to meet the electricity generation. But till now coal-based power plants are the major source of electricity generation. Disadvantages of coal-based thermal power plants is disposal problem of fly ash and pond ash. It was earlier considered as a total waste and environmental hazard thus its use was limited, but now its useful properties have been known as raw material for various application in construction field. Fly ash from the thermal plants is available in large quantities in fine and coarse form. Fine fly ash is used in construction industry in some amount and coarse fly ash is subsequently disposed over land in slurry forms. In India around 180 MT fly is produced and only around 45% of that is being utilized in different sectors. Balance fly ash is being disposed over land. It needs one acre of land for ash disposal to produce 1MW electricity from coal. Fly ash and pond ash utilization helps to reduce the consumption of natural resources. The fly ash became available in coal based thermal power station in the year 1930 in USA. For its gainful utilization, scientist started research activities and in the year 1937, R.E. Davis and his associates at university of California published research details on use of fly ash in cement concrete. This research had laid foundation for its specification, testing & usages. This study reports the potential use of pond-ash and fly-ash as cement in concrete mixes. In this present study of concrete produced using fly ash, pond ash and OPC 53 grade will be carried. An attempt will be made to investigate characteristics of OPC concrete with combined fly ash and pond ash mixed concrete for Compressive Strength test, Split Tensile Strength test, Flexural Strength test and Durability tests. This paper deals with the review of literature for fly-ash and pond-ash as partial replacement of cement in concrete.


2018 ◽  
Vol 276 ◽  
pp. 110-115
Author(s):  
Martin Ťažký ◽  
Martin Labaj ◽  
Rudolf Hela

The by-products of energy industry are nowadays often affected by new limits governing the production of harmful gases discharged into the air. These stricter and stricter criteria are often met by electricity producers by changing the combustion process in thermal power plants itself. Nowadays, the SNCR (selective non-catalytic reduction) application is quite common in the combustion process in order to help reduce the nitrogen oxide emission. This article deals with the primary measures of thermal power plants, which in particular consist of a modified treatment of raw materials (coal) entering the combustion process. These primary measures then often cause the formation of fly ash with unsuitable fineness for the use in concrete according to EN 450. The paper presents the comparison of the physico-mechanical parameters of several fly ashes with a different fineness values. The primary task is to assess the impact of non-suitable granulometry in terms of EN 450 on the other physico-mechanical parameters of fly ashes sampled within the same thermal power plant. Several fly ashes produced in the Czech Republic and surrounding countries were evaluated in this way.


2020 ◽  
Vol 2020 ◽  
pp. 1-6 ◽  
Author(s):  
Tuan Anh Nguyen

Fly ash, a waste product from thermal power plants, is one of the good alternatives for use as a filler in polymers, especially in flame retardants. Fly ash is an environmentally friendly fire retardant additive for composites, used in place of conventional flame retardant additives such as halogenated organic compounds, thus promoting environmental safety. In this study, fly ash was modified with stearic acid to improve adhesion at the polymers interface and increase compatibility. Fly ash was studied at various volumes (5, 10, and 20 wt.% fly ash) used in this study to synthesize fly ash-epoxy composites. The results show that the tensile strength, flexural strength, compressive strength, and impact strength of these synthetic materials increase when fly ash is modified to the surface, compressive strength: 197.87 MPa, flexural strength: 75.20 MPa, impact resistance: 5.77 KJ/m2, and tensile strength: 47.89 MPa. Especially, the fire retardant properties are improved at a high level, with a modified 20% fly ash content: the burning rate of 16.78 mm/min, minimum oxygen index of 23.2%, and meet the fire protection standard according to UL 94HB with a burning rate of 8.09 mm/min. Scanning electron microscopy (SEM) and infrared spectroscopy were used to analyze the morphological structure of fly ash after being modified and chemically bonded with epoxy resin background.


Author(s):  
H. S. Dhindsa ◽  
R. D. Sharma ◽  
Rakesh Kumar

The poor infiltration and fine texture of clay soil causes water logging problem and reduces biological activities in soil. In contrast to this, loose particle and higher in filterability in sandy soil results in low water holding capacity and poor nutrient retention. Fly ash, a waste product of thermal power plants, causes environmental pollution and is hazardous to human health. It is produced in plenty; therefore, safe disposal is very difficult. Fly ash may be used as amendment to improve soil properties and plant growth in such soils. The addition of 20% fly ash in clayey soil and up to 30% in sandy soils improved the germination, tillering, plant height, biological and grain yield of wheat. The addition of fly-ash has also shown improvement in the soil properties <italic>viz</italic>. texture, structure and bulk density. Permeability of clay loam soil increased from 0.54cm/hr to 2.14cm/hr by the addition of 50% fly ash whereas it decreased from 23.80 cm/hr to 9.67 cm/hr in sandy soil by 50% fly-ash addition. Water holding capacity of sandy soil also increased from 0.38 cm/cm to 0.53 cm/cm at 50% level.


2020 ◽  
Author(s):  
Milica Karanac ◽  
Maja Đolić ◽  
Vladimir Pavićević ◽  
Aleksandar Marinković

&lt;p&gt;Coal thermal power plants (TPP) actively generate numerous solid combustion by-products, including fly ash and bottom ash. These TPP by-products have already found use in a variety of civil engineering applications, such as a substitute for sand and gravel in structures, as well as a binding component in certain types of cement (generally, concrete and masonry). Furthermore, such by-products have become a subject of increasing interest in environmental engineering as a low-cost and effective adsorbent for the removal of organic pollutants and heavy metals from wastewaters.&lt;/p&gt;&lt;p&gt;In order to minimize the impact of material cost, novel solutions for the development of a high capacity and long-term adsorbent have provided a high performance adsorbent for practical applications. This study is focused on the use of modified fly ash (MFA) activated by lime (Ca(OH)&lt;sub&gt;2&lt;/sub&gt;) as an effective and low-cost adsorbent for the removal of As(V) ions. The adsorption capacity of the MFA adsorbent was found to be 35.40 mg g&lt;sup&gt;-1&lt;/sup&gt;, while the kinetic and thermodynamic parameters indicated a spontaneous and endothermic process. Due to the low desorption potential of the exhausted adsorbent (MFA/As(V), their effective further material reuse was established to be feasible. The reuse of the exhausted adsorbent was obtained through pozzolanic MFA particles and Ca(OH)&lt;sub&gt;2, &lt;/sub&gt;thereby formulating a construction material of a cementitious calcium-silicate hydrate. The toxicity leaching test (TCLP) and mechanical properties of the new construction material containing exhausted MFA (CM-MFA/As(V)) confirm its safe use in the laboratory as well as its semi-industrial application.&lt;/p&gt;&lt;p&gt;The specific objectives of this study have been: (i) to improve the adsorption performance of the MFA; (ii) to evaluate the material&amp;#8217;s equilibrium, as well as the process&amp;#8217; kinetic and thermodynamic aspects, including &amp;#160;estimating its limiting step; and (iii) to investigate the possible reuse of the exhausted adsorbent in the production of construction materials. The kinetic data were successfully fitted by a pseudo-second-order equation and the Weber-Morris model. The metal-desorption experiments performed on the exhausted FA and MFA indicate a low recovery of the selected pollutants.&lt;/p&gt;&lt;p&gt;The major outcome of this study, indicates that double-valorization of fly ash opens new directions for waste management toward reuse in effective practical applications; i.e., for actual water &amp;#8211;purification systems, as well as in the production of construction material.&lt;/p&gt;


2019 ◽  
Vol 281 ◽  
pp. 01010
Author(s):  
Samer Abou Kheir ◽  
Jad Wakim ◽  
Elie Awwad

The polypropylene (PP) fibers in shotcrete has been used for ground support and building strengthening, since several decades. However, the recent trend is to use the waste material in cementbased mixes to produce an eco-friendly material. Such waste material is the incineration fly ash (FA) that is classified as a hazardous product. This study is intended to establish the mechanical properties of fiber reinforced mortar in addition to cement or sand partial replacement by fly ash, in terms of flexural strength testing. The mechanical properties reflect the influence of the dosage of fiber content and the proportion of the fly ash on the flexural strength. The percentage of cement or sand was replaced by 0, 10, 20, and 30% fly ash. The dosage of fibers was 0, 0.6, 1.2, and 1.8 kg/m3. This green mix with fibers provides a partial substitute of cement as it is cheaper, by incorporating waste product, and saving energy consumption in the production. Due to growing interest in sustainable construction, engineers and architects are motivated to choose such materials which are more sustainable.


2020 ◽  
Vol 3 (2) ◽  
pp. 29-35 ◽  
Author(s):  
G. Medvedeva ◽  
A. Lifant'eva A.F.

the most important direction of resource saving in construction is the widespread use of secondary material resources, which are waste products. The use of secondary products of industry as raw materials for the production of various building materials is very important, because it provides production with rich sources of cheap and, often, already prepared raw materials; lead to lower costs for the production of some building materials, and therefore saves capital investments intended for the construction of buildings and structures; release large areas of land and reduce the impact on the environment. The article deals with heat-insulating and structural-heat-insulating materials, with partial replacement of components by ash-slag waste (ASW): lightweight concretes with broken glass and concretes modified with sulfur. Properties of concretes modified with sulfur are investigated: compressive strength, density and thermal conductivity. In accordance with the obtained properties, a comparative characteristics of the received materials with existing building materials was carried out: sulfur modified concrete and lightweight concrete; lightweight concrete using broken glass and claydite-concrete. Thermophysical calculation of multilayer hencing is made. In each of the options, one of the following materials was selected as a structural and heat-insulating material: lightweight concrete using broken glass and sulfur modified concrete. Also, for each type of hencing, the necessary heat-insulating and structural materials were selected. In the economic part, the cost of the raw materials necessary to obtain 1 m3 of the investigated materials and the cost of 1 m3 of multilayer hencing, which includes the investigated concrete, are calculated.


2019 ◽  
Vol 93 ◽  
pp. 02008
Author(s):  
Tribikram Mohanty ◽  
Sauna Majhi ◽  
Purnachandra Saha ◽  
Bitanjaya Das

Due to rapid industrialization extensive quantity of waste materials like fly ash, silica fume, rice ash husk, and ferrochrome ash etc. are generated. Ferrochrome ash is generated from Ferro-alloy industry and fly-ash is produced in thermal power plants are alternative materials which have the potential of being utilized in concrete as a mineral admixture. The present investigation considers the combined influence on strength of concrete using various percentage fly ash and ferrochrome ash as partial replacement of cement. Experiments are carried out to get mechanical properties of ordinary Portland cement by replacement of fly ash by 10%, 20%, 30 % and 3% by ferrochrome ash. Mechanical properties are measured by determining compressive strength, split tensile strength and flexural strength. It can be inferred from the study that a small amount of ferrochrome ash mixed with 30 % fly-ash gives higher compressive strength as compared to fly ash alone. Addition of ferrochrome ash also increases the split tensile strength of concrete. Since ferrochrome ash and fly-ash are both industrial waste, utilization of these waste materials reduced the burden of dumping and greenhouse gas and thereby produce sustainable concrete.


2016 ◽  
Vol 852 ◽  
pp. 55-60 ◽  
Author(s):  
A. Praveen Kumar ◽  
M. Nalla Mohamed ◽  
K. Kurien Philips ◽  
J. Ashwin

Increasing demand for special materials leads to new inventions. One of the most promising inventions is the concept of composites. Natural fibers have the potential as a reinforcing material as an alternative to the use of glass, carbon and other synthetic fibers in automotive industries. Among various natural fibers, Kenaf is a widely used fiber due to its easy availability, low density, low production cost and satisfactory mechanical properties. To enhance the mechanical properties of natural fibre composites, strengthening of the matrix and fibre is very much essential. A prospective reinforcement in this regard is fly ash, which is abundantly available as a waste product from thermal power plants. In this paper, a new novel natural composite with epoxy as a resin and reinforcing both bio waste (Kenaf) and industrial waste (Fly ash) has been developed. All the laminates were prepared with a total of 4 plies. Laminates without fly ash filler were also fabricated for comparison purpose. A hand lay-up method was used for the fabrication of composites and was tested as per ASTM standards for evaluation of tensile properties. The effect of fly ash weight percentage (5, 10, 15% wt.) on tensile properties was studied experimentally. Due to the incorporation of fly ash fillers into the kenaf fiber composites, there is considerable improvement in the mechanical properties. Overall results supported the effective utilization of natural composites for automotive applications.


2019 ◽  
Vol 8 (4) ◽  
pp. 11086-11091

A large quantity of waste materials such as fly ash, silica fume, rice ash husk, and ferrochrome ash etc. are produced as a result of rapid industrialization. Ferrochrome ash is derived from the ferro-alloy industry and fly-ash is developed in thermal power plants as substitute products that can be used as a mineral admixtureinconcrete. The present study considers concrete's structural behavior using different percentage of fly ash and ferrochrome ash as a partial replacement of cement. Experiments were performed tosubstitute cement with 10% fly as h, 20%, 30% and 3% ferrochrome ash. Beam specimens are prepared by following standard procedures. It can be inferred from the study that the sample with 30% fly ash and 3% ferrochrome ash as partial replacement of cement gives maximum load carrying capacity among all the beam specimens. Further, it is observed that the beam specimen with fly ash and ferrochrome ash gives more ductility than of conventional concrete. Hence 30% fly ash and 3% ferrochrome ash as partial replacement of cement has been strongly recommended.


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